NUR102 (Nutrition and Diet Therapy)
STUDENT ACTIVITY SHEET
BS NURSING / SECOND YEAR
Session # 11
LESSON TITLE: Water and the Minerals
LEARNING OUTCOMES:
At the end of the lesson, the nursing student can:
1. List the functions of water in body fluids;
2. Explain how the body regulates fluid, electrolyte, and acidbase balance;
3. Identify the main roles, deficiency and toxicity
symptoms, and food sources for each of the major
minerals; and,
4. Identify the main roles, deficiency and toxicity
symptoms, and food sources for each of the trace
minerals.
Materials:
Pen, paper, index card, book, and class list
Reference:
DeBruyne, L.K., Pinna, K., & Whitney E.,
(2016) Nutrition and Diet Therapy: Principles
and Practice 9th Edition USA: Cengage
Learning
LESSON PREVIEW/REVIEW (5 minutes)
Instruction: Enumerate all fat-soluble and water-soluble vitamins.
FAT-SOLUBLE VITAMINS
WATER-SOLUBLE VITAMINS
MAIN LESSON (30 minutes)
A. Water and Body Fluids
Water constitutes about 60 percent of an adult’s body weight and a higher percentage of a children. Every cell in the body
is bathed in a fluid of the exact composition that is best for that cell. The body fluids bring to each cell the ingredients it
requires and carry away the end products of the life-sustaining reactions that take place within the cell’s boundaries.
Without water, cells quickly die.
The water in the body fluids:
⎯ Carries nutrients and waste products throughout the body.
⎯ Maintains the structure of large molecules such as proteins and glycogen.
⎯ Participates in metabolic reactions.
⎯ Serves as the solvent for minerals, vitamins, amino acids, glucose, and many other small molecules so that they
can participate in metabolic activities.
⎯ Maintains blood volume.
⎯ Aids in the regulation of normal body temperature, as the evaporation of sweat from the skin removes excess heat
from the body.
⎯ Acts as a lubricant and cushion around joints and inside the eyes, spinal cord, and amniotic sac surrounding a
fetus in the womb. To support these and other vital functions, the body actively regulates its water balance
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B. Water Balance
The cells themselves regulate the composition and amounts of fluids within and surrounding them. The entire system of
cells and fluids remains in a delicate but firmly maintained state of dynamic equilibrium. Imbalances such as dehydration
and water intoxication can occur, but the body quickly restores the balance to normal if it can. The body controls both
water intake and water excretion to maintain water equilibrium
Water Intake Regulation. The body can survive for only a few days without water. In healthy people, thirst and satiety
govern water intake. When the blood becomes too concentrated (having lost water but not salt and other dissolved
substances), the mouth becomes dry, and the brain center known as the hypothalamus initiates drinking behavior. Thirst
lags behind the lack of water. A water deficiency that develops slowly can switch on drinking behavior in time to prevent
serious dehydration, but a deficiency that develops quickly may not. Also, thirst itself does not remedy a water deficiency;
a person must respond to the thirst signal by drinking. With aging, thirst sensations may diminish.
Water intoxication, on the other hand, is rare but can occur with excessive water consumption and kidney disorders that
reduce urine production. The symptoms may include severe headache, confusion, convulsions, and even death in
extreme cases. Excessive water ingestion (several gallons) within a few hours dilutes the sodium concentration of the
blood and contributes to a dangerous condition known as hyponatremia
Water Excretion Regulation. Water excretion is regulated by the brain and the kidneys. The cells of the brain’s
hypothalamus, which monitor blood salts, stimulate the pituitary gland to release antidiuretic hormone (ADH) whenever
the salts are too concentrated, or the blood volume or blood pressure is too low. ADH stimulates the kidneys to reabsorb
water rather than excrete it. Thus, the more water you need, the less you excrete. If too much water is lost from the body,
blood volume and blood pressure fall. Cells in the kidneys respond to the low blood pressure by releasing renin. Through
a complex series of events involving the hormone aldosterone, this enzyme also causes the kidneys to retain more water.
Again, the effect is that, when more water is needed, less is excreted.
Minimum Water Needed. These mechanisms can maintain water balance only if a person drinks enough water. The
body must excrete a minimum of about 500 milliliters (about ½ quart) each day as urine—enough to carry away the waste
products generated by a day’s metabolic activities. Above this amount, excretion adjusts to balance intake, so the more a
person drinks, the more dilute the urine becomes. In addition to urine, some water is lost from the lungs as vapor, some is
excreted in feces, and some evaporates from the skin. A person’s water losses from all of these routes total about 2½
liters (about 2½ quarts) a day on the average.
Signs of Mild and Severe Dehydration
Mild Dehydration
Loss of <5% Body Weight)
⎯ Thirst
⎯ Sudden weight loss
⎯ Rough, dry skin
⎯ Dry mouth, throat, body linings
⎯ Rapid pulse
⎯ Low blood pressure
⎯ Lack of energy; weakness
⎯ Impaired kidney function
⎯ Reduced quantity of urine;
concentrated urine
⎯ Decreased mental functioning
⎯ Decreased muscular work and
athletic performance
⎯ Fever or increased internal
temperature
⎯ Fainting
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Severe Dehydration
Loss of >5% Body Weight
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
Pale skin
Bluish lips and fingertips
Confusion; disorientation
Rapid, shallow breathing
Weak, rapid, irregular pulse
Thickening of blood
Shock; seizures
Coma; death
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C. Fluid and Electrolyte Balance
When mineral salts dissolve in water, they separate (dissociate) into charged particles known as ions, which can conduct
electricity. For this reason, a salt that dissociates in water is known as an electrolyte. * The body fluids, which contain
water and partly dissociated salts, are electrolyte solutions.
The body’s electrolytes are vital to the life of the cells and therefore must be closely regulated to help maintain the
appropriate distribution of body fluids. The major minerals form salts that dissolve in the body fluids; the cells direct where
these salts go; and the movement of the salts determines where the fluids flow because water follows salt.
Proteins in the cell membranes move ions into or out of the cells. These protein pumps tend to concentrate sodium and
chloride outside cells and potassium and other ions inside. By maintaining specific amounts of sodium outside and
potassium inside, cells can regulate the exact amounts of water inside and outside their boundaries.
Healthy kidneys regulate the body’s sodium, as well as its water, with remarkable precision. The intestinal tract absorbs
sodium readily, and it travels freely in the blood, but the kidneys excrete unneeded amounts. The kidneys actually filter all
of the sodium out of the blood; then they return to the bloodstream the exact amount the body needs to retain. Thus, the
body’s total electrolytes remain constant, while the urinary electrolytes fluctuate according to what is eaten.
D. Acid–Base Balance
Acid–Base Balance The body uses ions not only to help maintain water balance but also to regulate the acidity (pH) of its
fluids. Like proteins, electrolyte mixtures in the body fluids protect the body against changes in acidity by acting as
buffers—substances that can accommodate excess acids or bases.
The body’s buffer systems serve as a first line of defense against changes in the fluids’ acid–base balance. The lungs,
skin, gastrointestinal (GI) tract, and kidneys provide other defenses. Of these organ systems, the kidneys play the primary
role in maintaining acid–base balance. Thus, disorders of the kidneys impair the body’s ability to regulate its acid–base
balance, as well as its fluid and electrolyte balances.
E. The Major Minerals
The distinction between the major minerals and the trace minerals does not mean that one group is more important than
the other. A deficiency of the few micrograms of iodine needed daily is just as serious as a deficiency of the several
hundred milligrams of calcium. The major minerals are so named because they are present, and needed, in larger
amounts in the body than the trace minerals.
Although all the major minerals influence the body’s fluid balance, sodium, chloride, and potassium are most noted for that
role. For this reason, these three minerals are discussed first. Each major mineral also plays other specific roles in the
body. Sodium, potassium, calcium, and magnesium are critical to nerve transmission and muscle contractions.
Phosphorus and magnesium are involved in energy metabolism. Calcium, phosphorus, and magnesium contribute to the
structure of the bones. Sulfur helps determine the shape of proteins.
F. Minor Minerals
⎯ The body requires trace minerals in tiny amounts, and they function in similar ways—assisting enzymes all over the
body.
⎯ Eating a diet that consists of a variety of foods is the best way to ensure an adequate intake of these important
nutrients.
⎯ Many dietary factors, including the trace minerals themselves, affect the absorption and availability of these nutrients.
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CHECK FOR UNDERSTANDING (20 minutes)
You will answer and rationalize this by pair. This will be recorded as your quiz. One (1) point will be given to correct answer
and another one (1) point for the correct ratio. Superimpositions or erasures in you answer/ratio is not allowed. You are
given 20 minutes for this activity:
Multiple Choice
1. Three-fourths of the sodium in people’s diets comes from:
a. fresh meats.
b. home-cooked foods.
c. frozen vegetables and meats.
d. salt added to food by manufacturers.
ANSWER: ________
RATIO:___________________________________________________________________________________________
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2. Which mineral is critical to keeping the heartbeat steady and plays a major role in maintaining fluid and electrolyte
balance?
a. Sodium
b. Calcium
c. Potassium
d. Magnesium
ANSWER: ________
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RATIO:___________________________________________________________________________________________
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3. The two best ways to prevent age-related bone loss and fracture are to:
a. take calcium supplements and estrogen.
b. participate in aerobic activity and drink eight glasses of milk daily.
c. eat a diet low in fat and salt and refrain from smoking.
d. maintain a lifelong adequate calcium intake and engage in weight-bearing physical activity.
ANSWER: ________
RATIO:___________________________________________________________________________________________
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4. Foods high in iron that help prevent or treat anemia include:
a. green peas and cheese.
b. dairy foods and fresh fruits.
c. homemade breads and most fresh vegetables.
d. meat and dark green, leafy vegetables.
ANSWER: ________
RATIO:___________________________________________________________________________________________
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5. A deficiency of ___ is one of the world’s most common preventable causes of mental retardation.
a. zinc
b. iodine
c. selenium
d. magnesium
ANSWER: ________
RATIO:___________________________________________________________________________________________
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RATIONALIZATION ACTIVITY (THIS WILL BE DONE DURING THE FACE TO FACE INTERACTION)
The instructor will now rationalize the answers to the students. You can now ask questions and debate among yourselves.
Write the correct answer and correct/additional ratio in the space provided.
1. ANSWER: ________
RATIO:_______________________________________________________________________________________
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2. ANSWER: ________
RATIO:_______________________________________________________________________________________
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3. ANSWER: ________
RATIO:_______________________________________________________________________________________
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4. ANSWER: ________
RATIO:_______________________________________________________________________________________
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5. ANSWER: ________
RATIO:_______________________________________________________________________________________
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LESSON WRAP-UP (5 minutes)
You will now mark (encircle) the session you have finished today in the tracker below. This is simply a visual to help you
track how much work you have accomplished and how much work there is left to do.
You are done with the session! Let’s track your progress.
AL Activity: Muddiest Point:
In today’s session, what was least clear to you?
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